X-ray computed tomography (CT) has been used to carry out both external and internal dimensional analyses of manufactured objects. In some industries, this technique has become a standard practice for purposes of quality assurance, maintenance, and repair. Typically, an X-ray CT system is employed to obtain volumetric data comprising both external and internal dimensional data. However, when such analyses are carried out on highly contoured objects, it is not uncommon to encounter distortions in the external dimensional data. Such distortions may be caused by X-ray scatter or other X-ray transmission issues. These distortions preclude accurate analysis of either the external or internal features of such objects.
Attempts to correct or accommodate such distortions have employed computer-aided design (CAD) models. Such techniques have had limited success, however, because the analyzed object often varies from that in the CAD model, due to manufacturing issues, wear on the object, etc.